U.S. patent application number 12/627008 was filed with the patent office on 2010-06-17 for method and system for tissue treatment utilizing irreversible electroporation and thermal track coagulation.
This patent application is currently assigned to AngioDynamics, Inc.. Invention is credited to William M. Appling, Eamonn P. Hobbs, Robert M. Pearson.
Application Number | 20100152725 12/627008 |
Document ID | / |
Family ID | 42241438 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100152725 |
Kind Code |
A1 |
Pearson; Robert M. ; et
al. |
June 17, 2010 |
METHOD AND SYSTEM FOR TISSUE TREATMENT UTILIZING IRREVERSIBLE
ELECTROPORATION AND THERMAL TRACK COAGULATION
Abstract
A system for selectively ablating tissue is provided herein that
has at least one energy source that has a non-thermal energy source
and a thermal energy source, at least one probe, means for
selectively coupling the probe to one desired energy source of the
at least one energy source, means for selectively energizing the
non-thermal energy source of the at least one energy source to
apply non-thermal energy to at least a portion of the desired
region to ablate at least a portion of the desired region, and
means for selectively energizing the thermal energy source of the
at least one energy source during the withdrawal of the at least
one probe to thermally ablate tissue substantially adjacent to a
probe track.
Inventors: |
Pearson; Robert M.; (San
Jose, CA) ; Hobbs; Eamonn P.; (Queensbury, NY)
; Appling; William M.; (Granville, NY) |
Correspondence
Address: |
ANGLODYNAMICS, INC.
14 PLAZA DRIVE
LATHAM
NY
12110
US
|
Assignee: |
AngioDynamics, Inc.
Queensbury
NY
|
Family ID: |
42241438 |
Appl. No.: |
12/627008 |
Filed: |
November 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61122058 |
Dec 12, 2008 |
|
|
|
Current U.S.
Class: |
606/33 ;
606/41 |
Current CPC
Class: |
A61B 2018/2005 20130101;
A61B 18/12 20130101; A61N 1/327 20130101; A61B 18/1815 20130101;
A61N 1/403 20130101; A61B 2018/00613 20130101; A61B 18/18 20130101;
A61B 2018/00577 20130101 |
Class at
Publication: |
606/33 ;
606/41 |
International
Class: |
A61B 18/14 20060101
A61B018/14; A61B 18/18 20060101 A61B018/18 |
Claims
1. A method for selectively ablating tissue comprising: providing
at least one energy source, wherein the at least one energy source
comprises at least a non-thermal energy source and a thermal energy
source; providing at least one probe that is configured to be
selectively operatively coupled to a desired energy source of the
at least one energy source; positioning, via a probe track, at
least a portion of the at least one probe within a desired region
of a target tissue; selectively coupling the at least one probe to
the non-thermal energy source; selectively energizing the
non-thermal energy source to apply non-thermal energy from the
non-thermal energy source to at least a portion of the desired
region to ablate at least a portion of the desired region;
selectively coupling the at least one probe to the thermal energy
source; withdrawing the at least one probe from the desired region;
and selectively energizing the thermal energy source to apply
thermal energy during at least a portion of withdrawal of the at
least one probe to ablate tissue substantially adjacent to the
probe track.
2. The method of claim 1, wherein the non-thermal energy source is
selectively energizing for a desired period of time.
3. The method of claim 2, wherein the desired period of time is a
predetermined period of time.
4. The method of claim 3, wherein the desired period of time is a
plurality of predetermined periods of time.
5. The method of claim 1, further comprising, prior to selectively
coupling the at least one probe to the thermal energy source,
operatively decoupling the at least one probe from the non-thermal
energy source.
6. The method of claim 1, wherein the steps of selectively coupling
the at least one probe to the non-thermal energy source and
selectively coupling the at least one probe to the thermal energy
source is done manually.
7. The method of claim 1 or 6, wherein selectively coupling the at
least one probe to the non-thermal energy source and selectively
coupling the at least one probe to the thermal energy source
comprises actuating a switch to operatively select between the
non-thermal energy source and the thermal energy source.
8. The method of claim 1, wherein the thermal energy source is an
alternating current thermal energy source.
9. The method of claim 1, wherein the thermal energy source is a
direct current thermal energy source.
10. The method of claim 1, wherein said thermal energy source is
selected from a group consisting of: radiofrequency (RE), focused
ultrasound, microwaves, lasers, thermal electric heating, and
cryosurgery.
11. The method of claim 1, wherein the probed is selected from a
group consisting of: a monopolar electrode, a bipolar electrode,
and an electrode array.
12. The method of claim 1, wherein the target tissue is selected
from a group consisting of: digestive tissue, skeletal tissue,
muscular tissue, nervous tissue, endocrine tissue, circulatory
tissue, reproductive tissue, integumentary tissue, lymphatic
tissue, urinary tissue, and soft tissue.
13. The method of claim 1, wherein the target tissue is selected
from a group consisting of: liver tissue, prostate tissue, kidney
tissue, lung tissue, pancreas tissue, uterus tissue, breast tissue,
and brain tissue.
14. The method of claim 1, wherein the probe is selectively
energized with thermal energy to ablate tissue proximate a distal
end of the probe track and proximate to a boundary of the tissue
ablated by the non-thermal energy source.
15. The method of claim 1, wherein at least one energy source is
configured to release at least one pulse of energy for between
about 100 microseconds to about 100 seconds.
16. The method of claim 1, wherein at least one energy source is
configured to release at least one pulse of energy for between
about 100 microseconds to about 1 second.
17. The method of claim 1, wherein at least one energy source is
configured to at least one pulse of energy for between about 100
microseconds to about 1000 microseconds.
18. The method of claim 1, wherein the non-thermal energy source
and the thermal energy source comprised a selectively configurable
generator that can release energy so as to act as both the
non-thermal energy source and the thermal energy source.
19. A method for selectively ablating tissue comprising: providing
at least one energy source, wherein the at least one energy source
comprises at least a non-thermal energy source and a thermal energy
source; providing at least one probe that is configured to be
selectively operatively coupled to a desired energy source of the
at least one energy source; positioning, via a probe track, at
least a portion of the at least one probe within a desired region
of a target tissue; selectively coupling the at least one probe to
the non-thermal energy source; selectively energizing the
non-thermal energy source to apply non-thermal energy from the
non-thermal energy source to at least a portion of the desired
region to ablate at least a portion of the desired region; changing
at least one parameter on the non-thermal energy source;
withdrawing the at least one probe from the desired region; and
selectively energizing the thermal energy source to apply thermal
energy during at least a portion of withdrawal of the at least one
probe to ablate tissue substantially adjacent to the probe
track.
20. The method of claim 19 wherein the at least one parameter is
selected from a group consisting of: voltage, current, pulse
number, pulse duration, and a dwell between two pulses.
21. A system for selectively ablating tissue comprising: at least
one energy source, wherein the at least one energy source comprises
a non-thermal energy source and a thermal energy source; at least
one probe; means for selectively coupling the probe to one desired
energy source of the at least one energy source; means for
selectively energizing the non-thermal energy source of the at
least one energy source to apply non-thermal energy to at least a
portion of the desired region to ablate at least a portion of the
desired region; and means for selectively energizing the thermal
energy source of the at least one energy source during the
withdrawal of the at least one probe to thermally ablate tissue
substantially adjacent to a probe track.
22. The system of claim 21, wherein the means for selectively
coupling the probe to one desired energy source comprises means for
selectively switching between the non-thermal energy source and the
thermal energy source.
23. A system for selectively ablating tissue comprising: at least
one energy source, wherein the at least one energy source comprises
a non-thermal energy source and a thermal energy source; at least
one probe, wherein at least a portion of the probe is configured
for insertion therein a patient; means for selectively coupling the
probe to one desired energy source of the at least one energy
source; and means for selectively energizing the one desired energy
source to ablate at least a portion of the tissue adjacent to the
at least one probe.
24. The system of claim 23, wherein the means for selectively
energizing the one desired energy source comprises: means for
selectively energizing the non-thermal energy source of the at
least one energy source to apply non-thermal energy to at least a
portion of a desired region to ablate at least a portion of the
desired region; and means for selectively energizing the thermal
energy source of the at least one energy source during the
withdrawal of the at least one probe to thermally ablate tissue
substantially adjacent to a probe track.
25. The system of claim 24, wherein the means for selectively
coupling the probe to one desired energy source comprises means for
selectively switching between the non-thermal energy source and the
thermal energy source.
26. A method for selectively ablating tissue comprising: providing
at least one energy source, wherein the at least one energy source
comprises at least a non-thermal energy source and a thermal energy
source and at least one means for selectively adjusting at least
one parameter; providing at least one probe that is configured to
be selectively operatively coupled to the at least one energy
source; positioning, via a probe track, at least a portion of the
at least one probe within a desired region of a target tissue;
selectively coupling the at least one probe to the at least one
energy source; selectively adjusting the at least one parameter to
deliver non-thermal energy to the target tissue; selectively
energizing the at least one energy source to apply non-thermal
energy from the at least one energy source to at least a portion of
the desired region to ablate at least a portion of the desired
region; selectively adjusting the at least one parameter to deliver
thermal energy to the target tissue; withdrawing the at least one
probe from the desired region; and selectively energizing the at
least one energy source to apply thermal energy during at least a
portion of withdrawal of the at least one probe to ablate tissue
substantially adjacent to the probe track.
27. The method of claim 26, wherein the at least one parameter is
selected from group comprising: voltage, pulse duration, and pulse
number.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 61/122,058, filed Dec. 12, 2008, which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to systems and methods for
treating target regions of tissue. More particularly, the present
invention relates to a combination system and method for
non-thermally treating target regions of tissue and subsequently
thermally ablating tissue along a tissue track to coagulate blood
vessels and prevent track seeding.
BACKGROUND
[0003] Tumor ablation technology for medical treatment is known in
the art and includes such treatment modalities as radiofrequency
(RF), focused ultrasound, such as high intensity ultrasound beams,
microwave, laser, thermal electric heating, traditional heating
methods with electrodes using direct current (DC) or alternating
current (AC), and application of heated fluids and cold therapies
(such as cryosurgery, also known as cryotherapy or
cryoablation).
[0004] In many of these procedures an energy delivery device, such
as a probe with or without a needle, is inserted into a target
tissue to cause destruction of a target region of a tumor mass
through the application of energy, such as thermal energy,
non-thermal energy, and energy associated with cryo ablation
procedures. Upon insertion of the energy delivery device, a tissue
track is typically created. A tissue track is defined as the space
created by the insertion of a device extending from the skin
surface to the target tissue. When the energy delivery device is
removed, it is pulled back along the tissue track that had been
previously created upon insertion of the energy delivery device. As
the energy delivery device is being withdrawn, the tissue
immediately adjacent to the puncture site or tissue track is
ablated. The settings for the track ablation procedure can be
significantly lower than the ablation settings necessary for
non-tissue track ablation. This can produce a focalized zone around
the tissue track, maximizing the chance of death of unwanted
cellular material that may have adhered to the energy delivery
device, thereby preventing undesirable cell displacement, such as
in the movement of tumor cells that can re-seed to secondary
locations. It is known in the art that electrically induced thermal
ablation such as RF can be used to effectively and continuously
locally ablate a tissue track as an energy delivery device is being
removed to prevent tumor cell seeding and track bleeding. RF can
lead to coagulation necrosis in a margin surrounding normal tissue
where hyperthermic conditions lead to cellular injury such as
coagulation of cytosolic enzymes and damage to histone complexes,
leading to ultimate cell death. Although these tissue treatment
methods and systems can effectively ablate volumes of target
tissue, there are limitations to each technique. One often cited
problem using these procedures during tumor ablation involves heat
sink, a process whereby one aspect can include blood flow dragging
thermal energy away from a target tissue. This heat sink effect can
change both the shape and maximum volume of tissue that can be
treated. After treatment of a target tissue region with an energy
delivery device, upon removal of the energy delivery device from
the targeted tissue region, tumor cells can be pulled back with the
energy delivery device (i.e., seeding) along the tissue track or
bleeding can occur along the tissue track.
[0005] More recently, irreversible electroporation (IRE) has been
used as an alternative to the above-mentioned procedures to ablate
tumor tissue. However through IRE can be a nonthermal method
mediating cell death, it is not ideal for coagulation, and
specifically does not cause electrically induced thermal
coagulation, demonstrating the importance of using an alternative
source such as RF or long DC pulses in heating a tissue track.
Instead, IRE involves the application of electrical pulses to
target tumor tissue in the range of microseconds to milliseconds
that can lead to non-thermally produced defects in the cell
membrane that are nanoscale in size. These defects can lead to a
disruption of homeostasis of the cell membrane, thereby causing
irreversible cell membrane permeabilization which induces cell
necrosis, without raising the temperature of the tumor ablation
zone. During IRE ablation, connective tissue and scaffolding
structures are spared, thus allowing the surrounding bile ducts,
blood vessels, and connective tissue to remain intact. With
nonthermal IRE (hereinafter also called non-thermal IRE), cell
death is mediated through a nonthermal mechanism, so the heat sink
problem associated with many ablation techniques is nullified.
Therefore the advantages of IRE to allow focused treatment with
tissue sparing and without thermal effects can be used effectively
in conjunction with thermal treatment such as RF that has been
proven effective to prevent track seeding; this will also allow (in
this example embodiment) the user to utilize determined RF levels
leading to in some cases ablation and in some cases coagulation of
blood vessels of all sizes encountered during treatment; this is
important since IRE will not effectively coagulate when dealing
with large vessels. In this way the newly discovered advantages of
IRE can be utilized effectively with known techniques of thermal
damage including mediating tumor cell death and bringing about
coagulation along a tissue track.
[0006] Although IRE has distinct advantages, there are also
advantages of utilizing thermal ablation during withdrawal of
energy delivery devices from ablated tumor regions. Prior to the
disclosure of this invention, an invention had not been proposed
that could solve the problems of nonthermally ablating a target
region of tumor tissue, while maintaining integrity of the
surrounding tissue, and effectively switching to a device for
effectively thermally ablating tissue along the probe track. In
certain proposed embodiments, an energy delivery device can be
utilized that is powered by a single energy source that is capable
of application of energy in various forms, and subsequently
ablating a tissue track during withdrawal of the same energy
delivery device that can be powered by a different form of energy
from the same energy source, to prevent track seeding and minimize
bleeding. As indicated, IRE provides advantages for nonthermal cell
death and thermal mechanisms provide advantages for not only
preventing seeding, but also for effectively bringing about
coagulation. A need exists for a system and method that can provide
this combined non-thermal/thermal tumor ablation and that allows
for switching between non-thermal IRE energy delivery and thermal
energy delivery to increase tumor ablation efficiency and efficacy
and the prevention of tissue track seeding.
[0007] It is a purpose of this invention, in certain embodiments,
to provide a combination treatment system that has at least one
energy delivery device and at least one power or energy or power
source that is capable of providing IRE energy and thermal energy
to the energy delivery device. The at least one energy delivery
device can be either a monopolar or bipolar device. The system can
have at least one manual or automatic switching device for
switching the energy or power source from energy utilized in a
nonthermal form to energy in a thermal form to ablate target tumor
regions of tissue as well as tissue along a track.
[0008] It is a further purpose of this invention to provide a
method that involves using non-thermal IRE energy and thermal
energy to effectively ablate target regions of tissue. The method
involves positioning at least one energy delivery device that is
coupled to a single power source within a target region of a
tissue, applying IRE energy from the power source to the energy
delivery device which is used to ablate a target region of tissue,
while preventing damage to surrounding structures, then switching
from IRE energy to thermal energy using the same power source, and
withdrawing the energy delivery device while ablating a tissue
track with thermal energy such as RF energy, to allow for focal
tissue ablation and the safe and efficient withdrawal of the energy
delivery device used during the treatment procedure, while among
other things, coagulating tissue and preventing track seeding.
SUMMARY
[0009] What is described herein is a system and method for
selectively ablating tissue. In certain embodiments the method
involves providing application of IRE to treat tissue and treatment
of tissue with an alternative energy form (such as thermal energy)
to effectively ablate track tissue as a probe is withdrawn. The
method can involve providing at least one energy source which has
at least a non-thermal energy source and a thermal energy source,
providing at least one probe that is configured to be selectively
operatively coupled to a desired energy source of the at least one
energy source, positioning via a probe track at least a portion of
the at least one probe within a desired region of a target tissue,
selectively coupling the at least one probe to the non-thermal
energy source, selectively energizing the non-thermal energy source
to apply non-thermal energy from the non-thermal energy source to
at least a portion of the desired region to ablate at least a
portion of the desired region, selectively coupling the at least
one probe to the thermal energy source, withdrawing the at least
probe from the desired region, and selectively energizing the
thermal energy source to apply thermal energy during at least a
portion of withdrawal of the at least one probe to ablate tissue
substantially adjacent to the probe track.
[0010] A system for selectively ablating tissue is provided herein
that has at least one energy source that has a non-thermal energy
source and a thermal energy source, at least one probe, a means for
selectively coupling the probe to one desired energy source of the
at least one energy source, means for selectively energizing the
non-thermal energy source of the at least one energy source to
apply non-thermal energy to at least a portion of the desired
region to ablate at least a portion of the desired region, and
means for selectively energizing the thermal energy source of the
at least one energy source during the withdrawal of the at least
one probe to thermally ablate tissue substantially adjacent to a
probe track.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] A more complete understanding of the present invention can
be derived by referring to the detailed description when considered
in connection with the following illustrative figures. In the
figures, like reference numbers refer to like elements or acts
throughout the figures. Elements and method steps illustrated in
the figures are provided herein for simplicity and have not
necessarily been rendered according to any particular sequence or
embodiment.
[0012] FIG. 1A illustrates a perspective view of an ablation system
having a monopolar electrode.
[0013] FIG. 1B illustrates a perspective view of an ablation system
having a bipolar electrode.
[0014] FIG. 2 illustrates a perspective view of an ablation system
having a bipolar probe that is coupled to an energy source that is
capable of generating IRE energy and is inserted into target tissue
of a schematically-shown organ such as a liver.
[0015] FIG. 3 illustrates a plan view of one embodiment of a power
or energy source.
[0016] FIG. 4A illustrates a perspective view of the ablation
system of FIG. 2 in which the bipolar probe is being withdrawn
through a tissue track.
[0017] FIG. 4B illustrates a partial enlarged view of at least a
portion of the probe of FIG. 4A being withdrawn along a tissue
track where the probe is withdrawn farther in FIG. 4B than in FIG.
4A.
[0018] FIG. 5A is a flowchart illustrating a method of treatment
using a manual switching from an IRE energy source to a thermal
energy source.
[0019] FIG. 5B is a flowchart illustrating a method of treatment
using an automated switching from an IRE energy source to a thermal
energy source.
[0020] FIG. 6 shows a waveform including a depiction of a DC
current indicating how voltage and duration of pulse can be changed
for different treatment effects.
DETAILED DESCRIPTION
[0021] The present invention can be understood more readily by
reference to the following detailed description, examples, drawing,
and claims, and their previous and following description. However,
before the present devices, systems, and/or methods are disclosed
and described, it is to be understood that this invention is not
limited to the specific devices, systems, and/or methods disclosed
unless otherwise specified, as such can, of course, vary. It is
also to be understood that the terminology used herein is for the
purpose of describing particular aspects only and is not intended
to be limiting.
[0022] The following description of the invention is provided as an
enabling teaching of the invention in its best, currently known
embodiment. To this end, those skilled in the relevant art will
recognize and appreciate that many changes can be made to the
various aspects of the invention described herein, while still
obtaining the beneficial results of the present invention. It will
also be apparent that some of the desired benefits of the present
invention can be obtained by selecting some of the features of the
present invention without utilizing other features. Accordingly,
those who work in the art will recognize that many modifications
and adaptations to the present invention are possible and can even
be desirable in certain circumstances and are a part of the present
invention. Thus, the following description is provided as
illustrative of the principles of the present invention and not in
limitation thereof.
[0023] As used throughout, the singular forms "a," "an" and "the"
include plural referents unless the context clearly dictates
otherwise. Thus, for example, reference to "a tube segment" can
include two or more such tube segments unless the context indicates
otherwise. The term "plurality," as used herein refers to two or
more.
[0024] Ranges can be expressed herein as from "about" one
particular value, and/or to "about" another particular value. When
such a range is expressed, another aspect includes from the one
particular value and/or to the other particular value. Similarly,
when values are expressed as approximations, by use of the
antecedent "about," it will be understood that the particular value
forms another aspect. It will be further understood that the
endpoints of each of the ranges are significant both in relation to
the other endpoint, and independently of the other endpoint.
[0025] As used herein, the terms "optional" or "optionally" mean
that the subsequently described event or circumstance can or cannot
occur, and that the description includes instances where the event
or circumstance occurs and instances where it does not.
[0026] The term "distal" is understood to mean away from a medical
practitioner and towards the body site at which the procedure is
performed, and "proximal" means towards the medical practitioner
and away from the body site.
[0027] Referring now in detail to the drawings, in which like
reference numerals indicate like parts or elements throughout the
several views, in various embodiments, and referring to FIGS. 1-6,
presented herein is an exemplary system and method for treating
tumor tissue using a combination of IRE and thermal ablation.
[0028] Referring to FIG. 1A, one embodiment of an energy delivery
system 1 for selectively ablating tissue is illustrated. In one
aspect, the system 1 can comprise at least one energy delivery
device, such as, but not limited to, a monopolar probe 10, and at
least one energy delivery source or power source 15. In one aspect,
at least a portion of the probe 10 can be configured for insertion
into a patient. In one aspect, the at least one energy source 15
can further comprise at least a non-thermal energy source and a
thermal energy source. In one aspect, the system 1 can comprise a
mechanism for coupling the probe 10 to one desired energy source of
the at least one energy source 15.
[0029] In one aspect, although a monopolar probe 10 is described
herein, one of ordinary skill in the art will recognize that the
energy delivery device used with the system 1 described herein can
be a different type of energy delivery device, such as, but not
limited to, a bipolar probe 100, as illustrated in FIG. 1B. In one
aspect, the probe can be selected from a group consisting of: a
monopolar electrode, a bipolar electrode, and an electrode
array.
[0030] This can allow for utilization of an optimal energy delivery
device for a given medical procedure. In one aspect, the monopolar
probe 10 can comprise a handle 3, a needle 5 having a proximal end
and a distal end, and at least one connector 11 of the probe. In
one aspect, the needle 5 can comprise at least one electrode 7 that
is positioned therein at the distal end of the needle 5 and a
three-faced trocar tip 9 that is positioned therein at the distal
end of the needle 5 at the distal most portion of the needle 5. In
one aspect, the tip 9 can be a sharp tip and can be capable of
piercing tissue.
[0031] In one aspect, at least one monopolar probe 10, as described
above, can be used with system 1. In another aspect, although not
illustrated, at least two monopolar probes 10, as described above,
can be used with system 1. In one exemplary embodiment, it is
contemplated that if more than one probe 10 is used in the system
1, the probes 10 can be used in various configurations, such as,
but not limited to, a parallel configuration or a spiral
configuration. In one aspect, if two probes 10 are used, it is
contemplated that the tips 9 of each of the probes 10 can be
positioned such that tip 9 of a first probe 10 cannot extend
further than tip 9 of a second probe 10. In another exemplary
aspect, the probes 10 can be positioned such that the distal tip 9
of a first probe 10 can be staggered in length compared to a distal
tip 9 of a second probe 10. In one exemplary embodiment, if at
least two probes 10 are used in the system 1, the at least two
probes 10 can be spaced about 10 mm apart while inserted into
tissue and can provide a voltage of up to 2000 volts. In yet
another exemplary embodiment, the at least two probes 10 can be
spaced about 15 mm apart and can have a voltage of up to about 2500
volts. In one exemplary embodiment, the at least two probes 10 can
be spaced from each other such that they are approximately 40 mm
apart while inserted into a target tissue and can provide a voltage
of up to approximately 4000 volts.
[0032] In one aspect, the at least one electrode 7 of the monopolar
probe 10 can be configured to be electrically coupled to and
energized by energy source 15. Further, although not shown, one of
ordinary skill in the art would recognize that at least one
grounding pad can be used in conjunction with the at least one
electrode 7 to complete an electrical circuit. Although a single
electrode configuration is described herein, it is contemplated
that other various needle and/or electrode array formations could
be used in any of the embodiments described herein. An array herein
refers to an orderly arrangement of multiple probes. In one aspect,
this array could be a plurality or series of monopolar and/or
bipolar probes arranged in various shapes, configurations, or
combinations in order to allow for the ablation of multiple shapes
and sizes of target regions of tissue. Various array patterns can
reduce the need to reposition the electrode array during treatment
by allowing multiple selectively activatable electrode patterns. In
one aspect, the electrodes can be of different sizes and shapes,
such as, but not limited to, square, oval, rectangular, circular or
other shapes. In one aspect, the electrodes described herein can be
made of various materials known in the art.
[0033] In one aspect, the electrodes described herein can be
exposed up to various lengths. In one aspect, the electrodes can
have an exposed length of up to approximately 20 mm while inserted
into tissue, such as in the case where the at least two probes 10
are spaced up to approximately 10 mm apart. In another exemplary
aspect, the electrodes can have an exposed electrode length of up
to approximately 20 mm, such as in the case where the at least two
probes 10 are spaced approximately 40 mm apart. In yet another
aspect, the electrodes can be spaced at various distances from one
another. In one aspect, the electrodes can be spaced apart a
distance of from about 0.5 cm to about to 10 cm. In another
exemplary embodiment, the electrodes can be spaced apart a distance
of from about 1 cm to about 5 cm. In yet another embodiment, the
electrodes can be spaced apart a distance of between about 2 cm and
about 3 cm. In one exemplary aspect the electrode surface area can
vary. In one exemplary embodiment, the electrode surface area can
vary from about 0.1 cm.sup.2 to about 5 cm.sup.2. In yet another
exemplary embodiment, the electrodes can have a surface area of
between about 1 cm.sup.2 to about 2 cm.sup.2.
[0034] In one aspect, the system 1 can comprise a means for
selectively energizing a desired energy source to ablate at least a
portion of the tissue adjacent to the at least one probe 10. In one
aspect, the non-thermal energy source of the at least one energy
source can be selectively energized to apply non-thermal energy to
at least a portion of the desired tissue region to ablate at least
a portion of the desired tissue region. Thus, in one aspect, the
energy source 15 can be configured to deliver non-thermal energy,
such as, but not limited to, irreversible electroporation (IRE)
energy to target tissue. In one exemplary embodiment, the thermal
energy source can be an RF energy source. In one aspect, although
not shown, during use of the system 1, the at least one probe 10
can be selectively coupled to the non-thermal energy source, and
the non-thermal energy source can be selectively energized to apply
non-thermal energy from the non-thermal energy source to at least a
portion of the desired tissue region to ablate at least a portion
of the desired tissue region In one exemplary aspect, the at least
one energy source 15 can have at least one connector that is
configured for selective coupling to the at least one probe 10. In
one aspect, the energy source 15 can have a positive connector 20
and a negative connector 13. More particularly, the at least one
connector 11 of the probe 10 can be connected to the energy source
15 via at least one of the positive connector 20 and the negative
connector 13, as illustrated in FIG. 2.
[0035] In one exemplary embodiment, the power source or energy
source 15 can be a RITA.RTM. model 1500.times. electrosurgical
radiofrequency generator capable of delivering up to 250 watts of
RF power. One of ordinary skill in the art would recognize that a
variety of generator models could be used with the system 1
described herein. In one aspect, the generator can be powered by a
battery. In one aspect, the generator 15 can be connected to a
standard wall outlet that is capable of producing about 110 volts
or about 230 volts. In one aspect, the power supply can be capable
of being manually adjusted, depending on the voltage. In one
exemplary embodiment, the generator 15 can be capable of producing
a minimum voltage of about 100 volts to about 3000 volts. In one
aspect, at least one of the power outlets, generators, and battery
sources described herein can be used to provide voltage to the
target tissue during treatment. In yet another exemplary
embodiment, to achieve IRE ablation of the target region of tissue
47, the power source or generator 15 can be used to deliver IRE
energy to target tissue 47, including target tissue that can be
somewhat difficult to reach. In one aspect, an exemplary embodiment
of an IRE generator can include anywhere from 2 to 6 positive and
negative connectors, though one of ordinary skill in the art would
understand that other numbers of positive and negative connectors
and different embodiments of connectors could be used and may be
and necessary for optimal ablation configurations.
[0036] FIG. 1B illustrates a system 1 in which a bipolar probe 100
is used, such as that described in U.S. patent application Ser. No.
12/437,843, which application is incorporated herein by reference.
In one aspect, the bipolar probe 100 can comprise a handle 30,
needle 50 having a proximal end and a distal end, and at least one
probe connector 11. In one aspect, the needle 50 can comprise at
least one electrode 70 that is positioned therein at the distal end
of the needle 50 and a three-faced trocar tip 90 that is positioned
at a distal most portion of a distal end of needle 50. In one
aspect, the needle 50 can further comprise a first electrode 70
that is positioned at the distal most portion of the needle 50, a
second electrode 23 that is positioned proximal of the electrode
70, and at least one spacer 27 that can be positioned between and
adjacent to at least a portion of each of the first electrode 70
and the second electrode 23. In one aspect, at least a portion of a
distal portion of the second electrode 23 can abut at least a
proximal portion of spacer 27 and at least a distal portion of
spacer 27 can abut at least a portion of a proximal portion of the
first electrode 70. In one aspect, similar to monopolar probe 10,
the bipolar probe 100 can be coupled to a thermal energy source 15.
During use of the system 1, the probe 100 can be coupled to the
energy source 15. More particularly, in one exemplary aspect, at
least one connector 11 of the probe 100 can be connected to the
energy source 15 via at least one of the positive connector 20 and
the negative connector 13, as also described above.
[0037] FIG. 2 illustrates a perspective view of an ablation system
having a bipolar probe that is coupled to an energy source that is
capable of generating IRE energy and is inserted into target tissue
of a schematically-shown organ such as a liver. Shown is the energy
delivery system 1 including a bipolar probe with a handle 30,
needle 50, the at least one electrode 70, a second electrode 23,
the at least one spacer 27, and a three-faced trocar tip 90. Also
shown is an energy delivery or power system 15, and connectors 11
to connect the probe to the power source. Also shown is a liver 45,
a skin surface 60, the interstitial space 52, the target region of
tissue 47 in the liver and an additional area that is an outer edge
49 of the target region of tissue 47.
[0038] FIG. 3 illustrates an exemplary embodiment of a single power
source 150 that can be used in the ablation system 1 described
herein. In this embodiment the energy source of the system can be
capable of providing at least two energy sources, such as, but not
limited to, thermal energy or non-thermal energy. In one aspect,
the non-thermal energy source and the thermal energy source can
comprise a selectively configurable generator that can release
energy so as to act as either or both of the non-thermal energy
source and the thermal energy source. Thus, in one exemplary
aspect, the same power source or generator 150 can be reconfigured
to release energy for non-thermal treatment and for thermal
treatment. In one aspect the single power source 150 can also
comprise a switching mechanism, at least one switch 67, at least
one connector, and an intermediate switching unit 61. The system
can also comprise a means for selectively energizing the thermal
energy source of the at least one energy source during the
withdrawal of the at least one probe to thermally ablate tissue
substantially adjacent to a probe track. In one aspect, the means
for selectively coupling the probe to one desired energy source can
comprise a means for selectively switching between the non-thermal
energy source and the thermal energy source.
[0039] In one exemplary aspect, switch 67 can allow for automated
switching between a non-thermal energy source, such as, but not
limited to, IRE energy, and a thermal energy source. In one
exemplary embodiment, power source 150 can have a positive
connector 130 and a negative connector 200. In one aspect, the
intermediate switching unit 61 allows switching between IRE energy
source 63 and the thermal energy source 65. In one aspect, switch
67 can be activated to change the type of energy that is supplied
to the at least one energy delivery device or probe 100. In one
aspect, other power source configurations can include multiple
positive and negative connectors that can be used with monopolar
probes 10 or arrays where there are from 2 to 6 connectors
(positive and negative) or more, allowing for multiple ablation
shapes depending upon the number of probes utilized, as well as the
placement position and the exposed lengths of the energy delivery
devices or probes. In one aspect, the switch 67 can allow for
switching from IRE energy to thermal energy as well as thermal
energy to IRE energy. In one aspect, the mechanism for switching
from IRE to thermal energy and back can include, but is not limited
to, a switch, a toggle, or other mechanical or electrical devices
known in the art, such as a button. In another embodiment, the
switch 67 can be coupled to the energy delivery device or probe. In
one aspect, the switch 67 can be positioned directly on the energy
delivery device or probe so as to allow power switching using the
same hand that is used to manipulate the probe. FIG. 4A shows an
ablation system wherein bipolar probe 100 is involved in a method
of selectively ablating tissue described herein. In one aspect, at
least one connector 11 of bipolar probe 100 is coupled to energy
source 15. Although bipolar probe 100 is described herein in the
method of use, one of ordinary skill in the art would recognize
that a monopolar probe could also be used in the method of use
described herein. In one aspect, during the method of using the
system, at least a portion of bipolar probe 100 is inserted into
target tissue 47 that is located within a target organ, such as,
but not limited to a liver 45. In one aspect, the target tissue 47
can comprise diseased tissue, such as, but not limited to,
hepatocellular carcinoma tissue and metastatic liver cancer tissue.
The system and method described herein is advantageous in that it
allows for treatment of a multitude of tissues and conditions that
are in some cases either inoperable through conventional surgical
methods or where such surgery is contraindicated due to the status
of the tissue or condition, or due to other factors related to the
patient or procedure. In one aspect, as described above, energy
source 15 can be configured for delivery of IRE energy to ablate
target tissue 47. In one aspect, after the energy delivery device
is inserted through the skin 60 into a patient's target tissue 47,
as described above, the energy delivery device or probe 100 can
then be used to deliver energy to the tissue 47 in order to ablate
unwanted or diseased tissue (the position of the probe during
target tissue ablation is shown in FIG. 2). To achieve IRE ablation
of target tissue 47, standard power outlets, such as, but not
limited to, can be coupled to the energy delivery device to provide
energy to the system. One of ordinary skill in the art would
recognize that other types of power outlets known in the art can
also be used. In one aspect, any of the power outlets, generators,
or battery sources described herein can provide voltage to the
target tissue 47. Such voltage can be provided to tissue in the
range of from about 90 volts to about 230 volts. In another
exemplary embodiment such voltage can be provided to target tissue
47 at 50 volt intervals. In another exemplary aspect, such voltage
can be provided to target tissue 47 in the range of from about 90
volts to about 230 volts. In other exemplary embodiments the
voltage can be provided to tissue at approximately 50 volt
intervals. In yet another exemplary embodiment, the IRE power
source or generator 15 can be coupled to a standard wall outlet of
about 110 volts or about 230 volts with a manually adjustable power
supply, depending on the voltage. In another exemplary embodiment
the generator 15 can have a minimum voltage of about 100 volts to
about 3000 volts and can be adjustable at approximately 100 volt
intervals. In one exemplary embodiment, the generator 15 can be
programmable so as to operate between about 2 amps and about 50
amps. Other tests ranges can involve a lower maximum when
appropriate.
[0040] In one aspect, IRE tissue ablation can be performed with
variations such as those described in U.S. patent application Ser.
No. 10/571,162, which application is incorporated herein by
reference. In one aspect, various parameters, such as voltage,
current, pulse number, pulse duration, and the dwells between
pulses as can be adjusted to achieve desired treatment outcomes
during ablation including IRE ablation (the dwells between pulses
can be, in certain embodiments, from approximately zero to 250
microseconds, and in other embodiments can be up to a second in
length, and the dwell between two specific pulses can be of the
same or different length as the dwell between the two prior pulses
or the two subsequent pulses). Parameters can also include position
or placement of a probe or probes.
[0041] Depending on various parameters, such as voltage (including
application of DC or AC or both as well as voltage per square
centimeter), current, pulse number, pulse duration, and the dwell
between pulses applied to tissue, the tissue can be subjected to
reversible electroporation, irreversible electroporation, or
thermal damage (generally considered to be resistive heating).
Nonthermal IRE ablation involves ablation where the primary method
of cellular disruption leading to death is mediated via
electroporation (rather than factors such as effects of or
responses to heating). In certain embodiments, depending on the
parameters mentioned (including time that the resulting temperature
occurs), cellular death can be mediated via nonthermal IRE up to
approximately 50.degree. C. In certain embodiments cellular damage
from thermal heating occurs above approximately 50.degree. C. In
various embodiments, the parameters resulting in nonthermal IRE can
be changed to result in the death of cells via thermal heating. The
parameters can also be changed to from one having nonthermal IRE
effects to alternative settings where the changed parameters also
have nonthermal IRE effects.
[0042] More particularly, in one aspect, the total number of pulses
and pulse trains in various embodiments can be varied based on the
desired treatment outcome and the effectiveness of the treatment
for a given tissue. During delivery of non-thermal IRE energy to
target tissue, a voltage can be generated that is configured to
successfully ablate tissue. In one aspect, certain embodiments can
involve pulses between about 5 microseconds and about 62,000
milliseconds, while others can involve pulses of about 75
microseconds and about 20,000 milliseconds. In yet another
embodiment, the ablation pulse applied to the target tissue 47 can
be between about 20 microseconds and 100 microseconds. In one
aspect, the at least one energy source can be configured to release
at least one pulse of energy for between about 100 microseconds to
about 100 seconds and can be adjustable at 10 microsecond
intervals. In certain embodiments the electrodes described herein
can provide a voltage of about 100 volts per centimeter (V/cm) to
about 7,000 V/cm to the target tissue 47. In other exemplary
embodiments, the voltage can be about 200 V/cm to about 2000 V/cm
as well as from about 300 V/cm to about 1000 V/cm. Other exemplary
embodiments can involve voltages of about 2,000 V/cm to about
20,000 V/cm. In one exemplary aspect, the bipolar probe 100 can be
used at a voltage of up to about 2700 volts.
[0043] In one aspect, the number of pulses that can be used in IRE
ablation can vary. In certain exemplary embodiments the number of
pulses can be from about 1 pulse to about 15 pulses. In other
exemplary embodiments, groups of about 1 pulse to about 15 pulses
can be applied in succession following a gap of time between each
pulse group or pulse train. In one exemplary embodiment the gap of
time between groups of pulses can be about 0.5 second to about 10
seconds. In one aspect, pulses can be delivered to target tissue 47
using energy delivery devices, such as, but not limited to, probes,
needles, and electrodes. In one aspect, such energy delivery
devices can be of varying lengths suitable for use in procedures
such as, but not limited to, percutaneous, laparoscopic, and open
surgical procedures. In one aspect, the at least one energy source
can be configured to release at least one pulse of energy for
between about 100 microseconds to about 100 seconds. In one
exemplary aspect, the voltage described herein can be applied using
the bipolar probe 100 in pulses of 100 microseconds in length to a
target region of tissue. In one aspect, the voltage can be applied
in pulses of about 90 microseconds in groups of pulses or
pulse-trains of 10, with an interval between pulses of about 250
milliseconds and a time between pulse-trains of about 2
seconds.
[0044] In one exemplary aspect, at least two monopolar probes 10
can be used to ablate target tissue, such that a zone of ablated
tissue is produced that is approximately 22 mm.times.18 mm.times.12
mm. In one exemplary embodiment, two single probes 10 can be
configured so as to involve other ablation areas, including, but
not limited to, an ablation area of approximately 30 mm.times.25
mm.times.17 mm. One of ordinary skill in the art would be
understood that the ablation size and shape can be advantageously
varied with placement of the probes 10 and various probe types. In
one aspect, during treatment, an additional area surrounding an
outer edge 49 of the target region of tissue 47 is also ablated
(ablation of unwanted or diseased tissue is shown in FIG. 2). This
surrounding area of tissue 49 can be ablated in order to ensure
patient safety and the complete and adequate ablation of the target
region of tissue 47. In one aspect, during the method of use, the
tri-faced trocar tip 90 of the probe 100 is used to puncture a
patient's skin surface 60. In one aspect, the tip 90 and at least a
portion of the probe 100 is then advanced into interstitial space
52, the tissue space between organs, and further into target tissue
47. One of ordinary skill in the art would recognize that the
target region of tissue 47 can be any tissue from any organ where
ablation can be used to ablate unwanted or diseased tissue, such
as, but not limited to, digestive, skeletal, muscular, nervous,
endocrine, circulatory, reproductive, integumentary, lymphatic,
urinary tissue or organs, or other soft tissue or organs where
selective ablation is desired. Soft tissue can include, but is not
limited to, any tissue surrounding, supporting, or connecting other
body structures and/or organs. For example, soft tissue can include
muscles, tendons, ligaments, fascia, joint capsules, and other
tissue. More specifically, target tissue 47 can include, but is not
limited to, areas of the prostate (including cancerous prostate
tissue), the kidney (including renal cell carcinoma tissue), as
well as breast, lung, pancreas, uterus, and brain tissue, among
others.
[0045] FIG. 4A illustrates bipolar probe 100 coupled to energy
source 15. In this aspect, the energy source 15 can be a thermal
energy source. In one aspect, the non-thermal energy source can be
selectively energizing for a desired period of time. More
particularly, the period of time can be a predetermined period of
time. In yet another aspect, the period of time can be a plurality
of predetermined periods of time. In one aspect, the thermal energy
source is selected from the group consisting of radiofrequency
(RF), focused ultrasound, microwave, lasers, thermal electric
heating, traditional heating methods with electrodes using DC or AC
currents, and the application of heated fluids and cold therapies
(such as cryosurgery). RF energy is known in the art for effective
use in tumor ablation, though it is clear that any form of
temperature-mediated continuous ablation could be used at settings
known the art. In one aspect, after the energy delivery device is
inserted into target tissue 47, tissue is ablated, and the energy
delivery device is withdrawn through a tissue track 51, as
illustrated. In one aspect the thermal energy source can be an
alternating current thermal energy source. In yet another aspect,
the thermal energy source is a direct current thermal energy
source.
[0046] In one aspect, the probe track 51 can start at the point of
non-thermal ablation of the target region 47. In one aspect,
thermal ablation can be initiated at the start of the probe track
51 (the start of the probe track 51 can be seen in FIGS. 2, 4A, and
4B), which in one embodiment is applied to prevent tumor seeding.
As the energy delivery device or probe 100 is withdrawn, thermal
energy can be applied through the probe 100 to the target tissue
47. In one aspect, the probe is selectively energized with thermal
energy to ablate tissue proximate a distal end of the probe track
and proximate to a boundary of the tissue ablated by the
non-thermal energy source.
[0047] In one aspect, IRE treatment of target tissue 47, followed
by thermal ablation of at least one tissue track 51 can be
performed during procedures such as, but not limited to,
laparoscopic procedures and open surgical procedures. In one aspect
track 51 can be ablated during removal or repositioning of a probe
100 from a target region of tissue 47, as well as through a portion
of the interstitial space 52. FIG. 4B illustrates an enlarged
portion of FIG. 4A after the target tissue is treated with IRE
energy and where the probe has been farther withdrawn in FIG. 4B
than in FIG. 4A. In one aspect, after delivery of IRE energy to the
target tissue, an ablated region 55 of tissue remains. In one
aspect, ablated region 55 of tissue includes target tissue region
47 and the surrounding area of tissue 49 shown in FIG. 4A. In one
exemplary embodiment, after treatment of the target tissue using
IRE, treatment parameters can be reset to bring about thermal track
ablation. In one aspect, after IRE treatment of the target tissue,
the energy delivery device or probe is withdrawn through a tissue
track 51. In one aspect, upon withdrawal of the energy delivery
device or probe 100 (and in some cases repositioning) of the energy
delivery device through tissue track 51 to ablate tissue, a tissue
track is coagulated, and tumor cell seeding can be prevented. In
one aspect thermal energy, such as, but not limited to RF energy,
can be applied to the ablation track 51 during probe withdrawal
such that a track ablation zone 53 is created. In one aspect, the
track ablation zone 53 can be defined by a thin layer of tissue
immediately surrounding the probe track 51 that has been ablated.
In one aspect, the track ablation zone 53 is created in order to
define a cauterized zone and to prevent seeding as the probe 100 is
withdrawn from the tissue track 51. In another aspect the track
ablation zone 53 is created to stop bleeding. It is important to
prevent track seeding during probe withdrawal, especially during
procedures that could involve excess bleeding, such as those
involving tumor ablation of at least a portion of organs such as,
but not limited to, the liver 45, which is a highly vascularized
organ. In one aspect, the track ablation zone 53 can extend from
the total IRE ablation region 55, through a portion of the liver 45
into the interstitial space 52. In one aspect the track ablation
zone 53 can extend outside of the liver 45 and into the
interstitial space 52 but does not extend to skin surface 60 since
application of thermal energy close to the skin surface can cause
complications for patients.
[0048] In one aspect, the generator 15 used during the thermal
track ablation procedure can be configured to have various track
ablation settings and capabilities. In one exemplary aspect, the
RITA.RTM. 1500.times. generator described above can be used as an
RF energy source. In one aspect, the RF energy source can be used
to ablate track tissue using 25-50 watts of power. In other
exemplary aspects, one of ordinary skill in the art would recognize
that smaller or larger amounts of power can be used in various
embodiments, as necessary, in order to provide track ablation. In
one exemplary embodiment utilizing the 1500.times. generator, the
RF power source can provide AC power in addition to being used for
track ablation, while the IRE power source can be used to provide
DC power.
[0049] In one aspect, if a thermal energy source is used, it could
be used with a variety of techniques to bring about tissue
ablation. In one exemplary aspect, additional embodiments can
involve track ablation performed using one or more of
radiofrequency (RF), focused ultrasound, microwaves, lasers,
thermal electric heating, traditional heating methods with
electrodes using DC or AC currents, and application of heated
fluids and cold therapies, such as, but not limited to, that used
in cryosurgery. In one aspect h heat energy can be delivered in
certain embodiments via pulses that can be in a range of about 100
microseconds to about 10 seconds. In other exemplary embodiments
the at least one energy source can be configured to release or
deliver at least one pulse of heat energy in a range of about 100
microseconds to about 1 second. In yet another exemplary
embodiment, at least one energy source can release or deliver at
least one pulse of energy for between about 100 microseconds to
about 1000 microseconds. In yet another exemplary embodiment, at
least one pulse can be delivered in a range of from about 1
microsecond to about 100 microseconds.
[0050] In one exemplary embodiment thermal energy can be applied
such that it produces fluctuations in temperature to effect
treatment. In one aspect, the thermal energy provided to the tissue
can heat the target tissue to between about 50.degree. C. and about
105.degree. C. to bring about cell death. In one aspect the
temperature can be adjusted such that it can be lesser or greater
than this temperature range, depending on the exact rate of speed
of removal of the energy delivery device from the target tissue 47.
In one embodiment the temperature used is between about 105.degree.
C. and about 110.degree. C., although one of ordinary skill would
recognize that temperatures above about 105.degree. C. can cause
tissue vaporization. Ellis L, Curley S, Tanabe K. Radiofrequency
Ablation for Cancer; Current Indications, Techniques, and Outcomes,
N.Y.: Springer, 2004. In one exemplary embodiment, thermal energy
can be used to ablate approximately 2-3 mm of tissue surrounding
track 51. In one aspect this tissue thickness can be varied
depending upon various factors, such as, but not limited to, the
condition of the target tissue 47, the various parameters used, and
the treatment options.
[0051] In one embodiment the mechanisms through which the user sets
the parameters for bringing about IRE effects are changed to bring
about thermal results through thermal heating that is resistive
heating. In certain embodiments the mechanisms are reset such that
DC energy is applied to bring about thermal track ablation. In one
exemplary embodiment, track ablation can be performed using DC
current. In one aspect, the DC current can be used for heating the
target tissue 47 in the track 51. In one aspect, at least one pulse
of DC current can be delivered in one direction. In yet another
aspect, at least one pulse of DC current can be delivered from the
opposite direction of an electrical circuit. In one aspect, DC
current can be applied such that the temperature of the tissue 47
can be between about 42.degree. C. and about 110.degree. C. In one
aspect, the DC current can be applied such that thermal damage is
induced at a temperature as low as about 42.degree. C. In yet
another aspect, as the rate of probe removal increases, the DC
current can be applied to the target tissue 47 such that the
temperature can be from about 50.degree. C. to about 60.degree. C.
Davalos R, Mir L, Rubinsky B. Tissue Ablation with Irreversible
Electroporation. Annals of Biomedical Engineering, Vol.
33(2):223-231 (2005). One of ordinary skill in the art would
recognize that various lengths of DC pulses can be applied to bring
about effective track ablation. In yet other embodiments, AC pluses
can be applied as the energy delivery device is removed from the
target tissue 47 in stages.
[0052] In summary, the method for selectively ablating tissue
involves providing at least one energy source, such as a generator,
described above. In one aspect, the at least one energy source can
comprise at least a non-thermal energy source and a thermal energy
source, providing at least one probe that is configured to be
selectively manually operatively coupled to a desired energy source
of the at least one energy source, positioning, via a probe track,
at least a portion of the at least one probe within a desired
region of a target tissue. In one aspect, the selective coupling of
the probe to the thermal energy source comprises the actuating a
switch to operatively select between the non-thermal energy source
and the thermal energy source. Then at least one probe is
selectively coupled to the non-thermal energy source, and the
non-thermal energy source is selectively energized to apply
non-thermal energy from the non-thermal energy source to at least a
portion of the desired region to ablate at least a portion of the
desired region, selectively coupling the at least one probe to the
thermal energy source, withdrawing the at least probe from the
desired region, and selectively energizing the thermal energy
source to apply thermal energy during at least a portion of
withdrawal of the at least one probe to ablate tissue substantially
adjacent to the probe track. In one aspect, prior to selectively
coupling the at least one probe to the thermal energy source, the
at least one probe is operatively decoupled from the non-thermal
energy source.
[0053] FIG. 5A and FIG. 5B illustrate a flowchart of the method for
treating target tissue 47 using an IRE energy source and a thermal
energy source, respectively. In one aspect, treatment can be
alternated between IRE energy and thermal energy using a manual
switch, as depicted in FIG. 5A. The method is shown from the start
to stop point of FIG. 5A as acts 69 to 91. In the manual switching
procedure, a physician locates 69 a target region of tissue 47 such
as a tumor using technology known in the art such as ultrasound
imaging. In one aspect an energy delivery device or probe is
connected 71 to IRE energy source, and the energy delivery device
or probe is then inserted 73 into at least a portion of target
region of tissue 47 such as a tumor. In one aspect, the IRE
parameters are set 75 to the desired settings, and the target
region of tissue 47 can be ablated 77 using an IRE process that is
precise and that spares surrounding bile ducts, blood vessel, and
connective tissue. The probe is then manually disconnected 79 from
the IRE energy source, and the probe is connected 81 to a thermal
energy source, where a track ablation mode can be set 83 for
ablation of the tissue adjacent to the probe as the probe is
withdrawn through the probe track 85 and from the organ and into
the interstitial space in a direction toward the skin. In one
aspect, this method provides the advantage of a continuous ablation
of the tissue 47 as the probe 10/100 is removed. Ablation can be
continued as the probe 10/100 is withdrawn. After step 85, a user
can evaluate whether the probe 10/100 has been withdrawn from the
target tissue region 47 and is outside 87 the organ and into the
interstitial space 52. If the probe has not been withdrawn from the
organ and has not reached 89 the interstitial space 52, ablation
will continue, though after the probe 10/100 has been withdrawn 91
into the interstitial space 52, ablation will be stopped; certain
embodiments include stopping points between the organ exit site to
the skin surface.
[0054] Still referring to FIG. 5A, although the method described
involves the ablation of at least part of a target tissue region 47
within an organ, one of ordinary skill in the art will recognize
that in some embodiments the probe 10/100 can be withdrawn directly
from a tissue 47, such as, but not limited to, a tumor not
associated with an organ. In yet another aspect, the probe 10/100
can be withdrawn directly from an organ following ablation of at
least a part of the organ. In each of these embodiments, track
ablation continues until a point is reached in the interstitial
space before reaching the skin surface. In one aspect, either the
ablation is carried out directly from the target tissue region 47
and into the interstitial space 52, where the ablation can cease,
or the track ablation can be from the target tissue region 47
through at least part of an organ and into the interstitial space
52, where tissue ablation stops prior to reaching the skin.
[0055] FIG. 5B is a flowchart illustrating a method of automatic
switching from an IRE energy source to a thermal energy source
utilizing switching in a combination thermal/non-thermal unit
(93-115). Shown is that the tumor is located 93, a connection is
made to the IRE/thermal combination energy delivery device 95, the
probe is inserted into tissue such as a tumor 97, the mode is set
to IRE 99 and the IRE parameters are set 101. Once the tissue such
as a tumor is ablated 103, the mode can be set to thermal 105,
wherein the device can be used in certain embodiments to ablate
tissue (to supplement the IRE ablation that was performed). The
mode can be set to track ablation mode 107. The probe is withdrawn
while ablating with thermal energy 109, and ablation is stopped
once the ideal point is reached outside the organ or tumor or
target region (depending on question 111 and answers 113, 115)
[0056] In one aspect the switching outlined in FIG. 5B differs from
the switching of FIG. 5A in that instead of manual switching
between IRE and thermal energy sources, ablation is automatic
switched between IRE energy and thermal energy. In one aspect, this
embodiment can involve the use of a switch. In one embodiment, the
combination unit can include pre-set track ablation settings. In
one aspect, the pre-set track ablation settings can be chosen
through the push of a button or switch. In another exemplary
embodiment, a track ablation mode can be chosen in which settings
can be adjusted. One of ordinary skill in the art would understand
that other exemplary methods can include switching from an IRE
energy source to a thermal energy source or from a thermal energy
source to an IRE energy source, and that this switching can be
performed more than once. In one aspect, he switch can be thrown
multiple times as necessary in a given procedure. One of ordinary
skill in the art will recognize that the combined method of IRE
ablation of target regions of tissue 47 and thermal track ablation
can be used with other devices and procedures. Switching between
non-thermal or IRE energy and thermal energy is advantageous
because it allows non-thermal focal ablation of target tumor tissue
47 with tissue sparing and provides for continuous thermal track
ablation to prevent or eliminate problems such as seeding and
coagulation as the probe 10/100 is withdrawn through tissue track
51. In one exemplary aspect this combination non-thermal/thermal
ablation can be performed with a single probe 10/100. The use of a
single probe is advantageous because it allows for fewer puncture
sites, shortens and simplifies the treatment procedure, and causes
fewer traumas to the patient.
[0057] FIG. 6 shows a waveform including a depiction of a DC
current indicating how voltage and duration of pulse can be changed
for different treatment effects. More specifically, three pulses
(117) are shown that are of equal voltage (shown in the equivalent
of a Y-axis in FIG. 6) and duration to one another (that can be
seen by looking at the pulse in relation to the equivalent of an
X-axis for time in FIG. 6), and a fourth pulse (119) is also shown
that is of greater voltage and greater duration than the previous
three pulses (117). This depiction indicates that in certain
embodiments target tissue can be ablated using a setting such as
117 to produce IRE nonthermally, and that the DC voltage can be
increased and the duration of the pulse increased to cause a
certain effect on tissue; in various embodiments the target tissue
would be ablated by application of pulses 117, and a single pulse
or multiple pulses of greater voltage as well as greater duration
(or both) can be applied for part of or the entire time of
withdrawal of the probe from the site of ablation to the point
exiting the body where the level of voltage and duration lead to
thermal effects from resistive heating for preventing tumor
seeding, coagulating blood vessels, or both.
[0058] Still referring to FIG. 6, in various embodiments 119 is
more than one pulse that is simply longer in duration than any of
the pulses in 117 but which mediate thermal heating via resistive
heating. Also, the thermal heating can be brought about by changing
119 such that the pulses are greater in number, the pulses are
longer, the dwell between pulses is smaller, or the voltage is
higher. It is also conceivable to alter one or both the voltage as
well as pulses to increase or decrease either or both (including
having the option to vary time between pulses) to bring about
thermal effects for track ablation. In certain embodiments the
change from pulses leading to IRE effects 117 to the pulse or
pulses leading to thermal effects 119 are used to bring about IRE
and thermal effects on tissue where both effects are within the
target region. Also, in certain embodiments the order of
application of pulses 117 and pulse or pulses 119 is switched in
the target region or in the tissue track or both to most
effectively treat the patient (so application of 119 could be
before 117). Also, pulses 117, and pulse or pulses 119 can be used
in conjunction with thermal heating methods such as Radiofrequency
such that nonthermal IRE effects, effects from resistive heating
due to DC current changes (such as that shown in 119), and thermal
heating effects from AC current (such as RF) can be brought about
in any order in target tissue or in a tissue track for the benefit
of the patient. For example, a tumor mass can be treated with IRE
or RF (or other AC as well as other DC pulses leading to resistive
heating) or more than one of these in any order so as to ablate the
target tissue or tissues and control bleeding or coagulate or
ablate vessels or cells, and then upon probe removal, IRE or RF (or
other AC as well as other DC pulses leading to resistive heating)
pulses can be uses as necessary together or independently in any
order to control bleeding, coagulate or ablate vessels, ablate
tumor cells, or to ablate or treat tissue surrounding the track. In
certain embodiments the changes between treatments or treatment
methods can be brought about using a mechanism or device or system
for altering or changing one or more parameters herein described
via an energy source; the source could have one or more generators
coupled and parameters could be determined using mechanisms of a
system or a generator or energy source, and the mechanisms could
have control components allowing user changes from a probe directly
or from the energy source directly.
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